> For the complete documentation index, see [llms.txt](https://openai.gitbook.io/code-cheatsheets/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://openai.gitbook.io/code-cheatsheets/js/dates.md). # Dates For more accuracy use, [window.performance.now()](https://stackoverflow.com/questions/6233927/microsecond-timing-in-javascript) ```javascript Date() // => "Tue Jan 21 2020 23:50:09 GMT-0800 (Pacific Standard Time)" let x = new Date() //create Date object x.toDateString(); //=> "Tue Jan 21 2020" x.toISOString(); //=> "2018-12-31T03:21:15.934Z" x.toGMTString(); //=> "Wed, 22 Jan 2020 07:48:33 GMT" x.toLocaleDateString(); //=> "1/21/2020" ``` *Parsing dates with `new Date()` varies across browsers,* [*recommended against*](https://stackoverflow.com/questions/33908299/javascript-parse-a-string-to-date-as-local-time-zone) ## [DateFns](https://date-fns.org/docs/Getting-Started) ``` npm install date-fns ``` Better than moment b/c selective importing and uses normal js date object `<` and `>` works on Date objects but **not** `==` or `===` ```js import { format, compareAsc } from 'date-fns' // Add any duration to 1 September 2014, 10:19:50 const result = add(new Date(2014, 8, 1, 10, 19, 50), { years: 2, months: 24, days: 7, hours: 5, minutes: 9, seconds: 30, }) ``` ### Formatting ```js import { format, formatDistance, formatRelative, subDays } from 'date-fns' format(new Date(), "'Today is a' iiii") //=> "Today is a Thursday" formatDistance(subDays(new Date(), 3), new Date()) //=> "3 days ago" formatRelative(subDays(new Date(), 3), new Date()) //=> "last Friday at 7:26 p.m." ``` #### Formatting Strings | Unit | Pattern | Result examples | Notes | | ------------------------------- | -------- | --------------------------------- | ----- | | Era | G..GGG | AD, BC | | | | GGGG | Anno Domini, Before Christ | 2 | | | GGGGG | A, B | | | Calendar year | y | 44, 1, 1900, 2017 | 5 | | | yo | 44th, 1st, 0th, 17th | 5,7 | | | yy | 44, 01, 00, 17 | 5 | | | yyy | 044, 001, 1900, 2017 | 5 | | | yyyy | 0044, 0001, 1900, 2017 | 5 | | | yyyyy | ... | 3,5 | | Local week-numbering year | Y | 44, 1, 1900, 2017 | 5 | | | Yo | 44th, 1st, 1900th, 2017th | 5,7 | | | YY | 44, 01, 00, 17 | 5,8 | | | YYY | 044, 001, 1900, 2017 | 5 | | | YYYY | 0044, 0001, 1900, 2017 | 5,8 | | | YYYYY | ... | 3,5 | | ISO week-numbering year | R | -43, 0, 1, 1900, 2017 | 5,7 | | | RR | -43, 00, 01, 1900, 2017 | 5,7 | | | RRR | -043, 000, 001, 1900, 2017 | 5,7 | | | RRRR | -0043, 0000, 0001, 1900, 2017 | 5,7 | | | RRRRR | ... | 3,5,7 | | Extended year | u | -43, 0, 1, 1900, 2017 | 5 | | | uu | -43, 01, 1900, 2017 | 5 | | | uuu | -043, 001, 1900, 2017 | 5 | | | uuuu | -0043, 0001, 1900, 2017 | 5 | | | uuuuu | ... | 3,5 | | Quarter (formatting) | Q | 1, 2, 3, 4 | | | | Qo | 1st, 2nd, 3rd, 4th | 7 | | | QQ | 01, 02, 03, 04 | | | | QQQ | Q1, Q2, Q3, Q4 | | | | QQQQ | 1st quarter, 2nd quarter, ... | 2 | | | QQQQQ | 1, 2, 3, 4 | 4 | | Quarter (stand-alone) | q | 1, 2, 3, 4 | | | | qo | 1st, 2nd, 3rd, 4th | 7 | | | qq | 01, 02, 03, 04 | | | | qqq | Q1, Q2, Q3, Q4 | | | | qqqq | 1st quarter, 2nd quarter, ... | 2 | | | qqqqq | 1, 2, 3, 4 | 4 | | Month (formatting) | M | 1, 2, ..., 12 | | | | Mo | 1st, 2nd, ..., 12th | 7 | | | MM | 01, 02, ..., 12 | | | | MMM | Jan, Feb, ..., Dec | | | | MMMM | January, February, ..., December | 2 | | | MMMMM | J, F, ..., D | | | Month (stand-alone) | L | 1, 2, ..., 12 | | | | Lo | 1st, 2nd, ..., 12th | 7 | | | LL | 01, 02, ..., 12 | | | | LLL | Jan, Feb, ..., Dec | | | | LLLL | January, February, ..., December | 2 | | | LLLLL | J, F, ..., D | | | Local week of year | w | 1, 2, ..., 53 | | | | wo | 1st, 2nd, ..., 53th | 7 | | | ww | 01, 02, ..., 53 | | | ISO week of year | I | 1, 2, ..., 53 | 7 | | | Io | 1st, 2nd, ..., 53th | 7 | | | II | 01, 02, ..., 53 | 7 | | Day of month | d | 1, 2, ..., 31 | | | | do | 1st, 2nd, ..., 31st | 7 | | | dd | 01, 02, ..., 31 | | | Day of year | D | 1, 2, ..., 365, 366 | 9 | | | Do | 1st, 2nd, ..., 365th, 366th | 7 | | | DD | 01, 02, ..., 365, 366 | 9 | | | DDD | 001, 002, ..., 365, 366 | | | | DDDD | ... | 3 | | Day of week (formatting) | E..EEE | Mon, Tue, Wed, ..., Sun | | | | EEEE | Monday, Tuesday, ..., Sunday | 2 | | | EEEEE | M, T, W, T, F, S, S | | | | EEEEEE | Mo, Tu, We, Th, Fr, Su, Sa | | | ISO day of week (formatting) | i | 1, 2, 3, ..., 7 | 7 | | | io | 1st, 2nd, ..., 7th | 7 | | | ii | 01, 02, ..., 07 | 7 | | | iii | Mon, Tue, Wed, ..., Sun | 7 | | | iiii | Monday, Tuesday, ..., Sunday | 2,7 | | | iiiii | M, T, W, T, F, S, S | 7 | | | iiiiii | Mo, Tu, We, Th, Fr, Su, Sa | 7 | | Local day of week (formatting) | e | 2, 3, 4, ..., 1 | | | | eo | 2nd, 3rd, ..., 1st | 7 | | | ee | 02, 03, ..., 01 | | | | eee | Mon, Tue, Wed, ..., Sun | | | | eeee | Monday, Tuesday, ..., Sunday | 2 | | | eeeee | M, T, W, T, F, S, S | | | | eeeeee | Mo, Tu, We, Th, Fr, Su, Sa | | | Local day of week (stand-alone) | c | 2, 3, 4, ..., 1 | | | | co | 2nd, 3rd, ..., 1st | 7 | | | cc | 02, 03, ..., 01 | | | | ccc | Mon, Tue, Wed, ..., Sun | | | | cccc | Monday, Tuesday, ..., Sunday | 2 | | | ccccc | M, T, W, T, F, S, S | | | | cccccc | Mo, Tu, We, Th, Fr, Su, Sa | | | AM, PM | a..aa | AM, PM | | | | aaa | am, pm | | | | aaaa | a.m., p.m. | 2 | | | aaaaa | a, p | | | AM, PM, noon, midnight | b..bb | AM, PM, noon, midnight | | | | bbb | am, pm, noon, midnight | | | | bbbb | a.m., p.m., noon, midnight | 2 | | | bbbbb | a, p, n, mi | | | Flexible day period | B..BBB | at night, in the morning, ... | | | | BBBB | at night, in the morning, ... | 2 | | | BBBBB | at night, in the morning, ... | | | Hour \[1-12] | h | 1, 2, ..., 11, 12 | | | | ho | 1st, 2nd, ..., 11th, 12th | 7 | | | hh | 01, 02, ..., 11, 12 | | | Hour \[0-23] | H | 0, 1, 2, ..., 23 | | | | Ho | 0th, 1st, 2nd, ..., 23rd | 7 | | | HH | 00, 01, 02, ..., 23 | | | Hour \[0-11] | K | 1, 2, ..., 11, 0 | | | | Ko | 1st, 2nd, ..., 11th, 0th | 7 | | | KK | 01, 02, ..., 11, 00 | | | Hour \[1-24] | k | 24, 1, 2, ..., 23 | | | | ko | 24th, 1st, 2nd, ..., 23rd | 7 | | | kk | 24, 01, 02, ..., 23 | | | Minute | m | 0, 1, ..., 59 | | | | mo | 0th, 1st, ..., 59th | 7 | | | mm | 00, 01, ..., 59 | | | Second | s | 0, 1, ..., 59 | | | | so | 0th, 1st, ..., 59th | 7 | | | ss | 00, 01, ..., 59 | | | Fraction of second | S | 0, 1, ..., 9 | | | | SS | 00, 01, ..., 99 | | | | SSS | 000, 001, ..., 999 | | | | SSSS | ... | 3 | | Timezone (ISO-8601 w/ Z) | X | -08, +0530, Z | | | | XX | -0800, +0530, Z | | | | XXX | -08:00, +05:30, Z | | | | XXXX | -0800, +0530, Z, +123456 | 2 | | | XXXXX | -08:00, +05:30, Z, +12:34:56 | | | Timezone (ISO-8601 w/o Z) | x | -08, +0530, +00 | | | | xx | -0800, +0530, +0000 | | | | xxx | -08:00, +05:30, +00:00 | 2 | | | xxxx | -0800, +0530, +0000, +123456 | | | | xxxxx | -08:00, +05:30, +00:00, +12:34:56 | | | Timezone (GMT) | O...OOO | GMT-8, GMT+5:30, GMT+0 | | | | OOOO | GMT-08:00, GMT+05:30, GMT+00:00 | 2 | | Timezone (specific non-locat.) | z...zzz | GMT-8, GMT+5:30, GMT+0 | 6 | | | zzzz | GMT-08:00, GMT+05:30, GMT+00:00 | 2,6 | | Seconds timestamp | t | 512969520 | 7 | | | tt | ... | 3,7 | | Milliseconds timestamp | T | 512969520900 | 7 | | | TT | ... | 3,7 | | Long localized date | P | 04/29/1453 | 7 | | | PP | Apr 29, 1453 | 7 | | | PPP | April 29th, 1453 | 7 | | | PPPP | Friday, April 29th, 1453 | 2,7 | | Long localized time | p | 12:00 AM | 7 | | | pp | 12:00:00 AM | 7 | | | ppp | 12:00:00 AM GMT+2 | 7 | | | pppp | 12:00:00 AM GMT+02:00 | 2,7 | | Combination of date and time | Pp | 04/29/1453, 12:00 AM | 7 | | | PPpp | Apr 29, 1453, 12:00:00 AM | 7 | | | PPPppp | April 29th, 1453 at ... | 7 | | | PPPPpppp | Friday, April 29th, 1453 at ... | 2,7 | ## Moment.js (Similar to Dayjs) ### Creation ```js moment(String); moment("12-25-1995", "MM-DD-YYYY"); //pass format of string ``` ### Formatting ```javascript //This one is the best because string sorting works moment().format(); // 2019-04-28T23:22:28-07:00 moment().format('MMMM Do YYYY, h:mm:ss a'); // April 28th 2019, 11:22:28 pm moment().format('dddd'); // Sunday moment().format("MMM Do YY"); // Apr 28th 19 moment().format('YYYY [escaped] YYYY'); // 2019 escaped 2019 ``` ### Operations ```javascript let today = moment(); today.add(config.add_days, 'days'); today.subtract(1, "days"); ``` **Get And Setters** Leave empty to get and give Number/String to set ```js moment().month();//return 0-11 which is Jan-Dec moment().day();//return 0-6 which is Sun-Sat moment().date(); //return 1-31 for day of month ``` #### Operations ```js moment('2016-10-30').isBetween('2016-10-30', '2016-12-30', null, '()'); //false moment('2016-10-30').isBetween('2016-10-30', '2016-12-30', null, '[)'); //true ``` ### Plugins #### [moment-business-days](https://github.com/kalmecak/moment-business-days) Only work with business days adding fts like isHoliday and businessDiff to moment